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Earlier this week, the blogging platform Tumblr announced it would be scrubbing itself of “adult content.” The move doesn’t just affect how people look at and exchange nude photos on a downtrodden platform—it portends a broad shift in how we experience intimacy and connection online, in how user-generated content is managed, and in how tech maintains its stranglehold on the digital commons.

The “adult content” Tumblr will be banning, the company wrote, “primarily includes photos, videos, or GIFs that show real-life human genitals or female-presenting nipples, and any content—including photos, videos, GIFs and illustrations—that depicts sex acts.” But what the company is really going after is a four-letter word strangely missing from its 538-word announcement: porn. Tumblr may be home to personal blogs, community forums, and foodie photo collections, but pornography makes up a huge part of its reputation. A friend of mine texted me that Tumblr ending porn is like “McDonalds ending hamburgers.”

Tumblr’s decision was partly motivated by a large child-porn problem. Rather than pay for the expensive work of patrolling the ages of people in porn, you can see why the company would simply want to overcorrect. But its “adult content” wasn’t strictly limited to porn. It is—was— a haven community for people who might not be able to connect sexually in other ways. As a reader who might be described as a member of the “cub” gay subculture wrote to me, “porn and related content on tumblr was the primary place I first saw more natural body types for guys.” Besides Tumblr, he said, there hasn’t always been “any place guys who are average to larger without growing six packs could admire themselves and other guys.”

Just as Black Twitter gave voice and audience to black writers, Tumblr created the space for sexually nonnormative people to see and be seen in ways they weren’t elsewhere. There were Tumblrs for those who identify as bears, furries, HIV-positive, bisexual, disabled, and fat; for people into S&M, pegging, and group masturbation. Whatever your body type or fetish, there was probably a Tumblr community for you.

This is the end point of user-generated content on any social-media platform: When people create content that has social benefit for them, it makes massive capital benefit for Silicon Valley and Wall Street. Yet the people who generate that wealth have no influence over the digital commons where it resides and no recourse if they’re evicted from it. The commons are, after all, privately owned—never really commons to begin with.

Why is this so broadly dangerous? Because it’s not easy to opt out of using digital platforms, which are becoming as important as physical roads for human interaction. Professional, commercial, and even the sexual interactions that literally determine life itself are mediated through these privately controlled communications networks. And as the power of these networks is consolidated, the people who’ve built them up but who are deemed a threat to maximum profit—even as collateral damage in a purge of illegal material—will be jettisoned.

Using social media intimately in our lives hasn’t been all bad. Indeed, as a recent scientific article by Oliver Haimson on some 240 Tumblr gender “transition blogs” showed, social media can play “an important role in adding complexity to people’s experiences managing changing identities during life transitions.” In fact, “female-presenting nipples” will be allowed under Tumblr’s new adult-content ban if they are shown “in connection with breastfeeding, birth or after-birth moments, and health-related situations, such as post-mastectomy or gender confirmation surgery.” Tumblr will also allow “nudity related to political or newsworthy speech, and nudity found in art, such as sculptures and illustrations.”

But theTumblr adult-content purge reveals the enormous cultural authority, financial extraction and what the philosopher Michael Foucault called “biopower” that tech companies wield over our lives.As intimate interactions are ever more mediated by tech giants, that power will only increase, and more and more of our humanity is bound to be mediated through content moderation. That moderation is subjective, culturally specific, and utterly political. And Silicon Valley doesn’t have a sterling track record of getting it right.